* fix: prevent OOM when handling large base64 image data
- Add memory-safe parseDataUrl utility using string operations instead of regex
- Truncate large base64 data in ErrorBlock detail modal to prevent freezing
- Update ImageViewer, FileStorage, messageConverter to use shared parseDataUrl
- Deprecate parseDataUrlMediaType in favor of shared utility
- Add GB support to formatFileSize
- Add comprehensive unit tests for parseDataUrl (18 tests)
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Co-Authored-By: Claude <noreply@anthropic.com>
* refactor: simplify parseDataUrl API to return DataUrlParts | null
- Change return type from discriminated union to simple nullable type
- Update all call sites to use optional chaining (?.)
- Update tests to use toBeNull() for failure cases
- More idiomatic and consistent with codebase patterns (e.g., parseJSON)
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Co-Authored-By: Claude <noreply@anthropic.com>
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Co-authored-by: Claude <noreply@anthropic.com>
